R-R intervals of ECG in depression.

ECG measurements of consecutive 100 R-R intervals were done on depressive patients. The patient group presented lower mean values for coefficients of variation (CV) at each generation than the control group (normal subjects); the differences were significant especially for the subjects 40 to 49 years of age (P less than 0.05) and for those 60 to 69 years of age (P less than 0.01). These results can probably be regarded as a significant and objective index of autonomic disturbances in depression.